No, it just means that the crankshaft was internally balanced, so it doesn't need a weighted balancer or flywheel to balance it. I mentioned cutting the counterweights down and making the crankshaft lighter just to aid in how much weight is being thrown around at high rpm.
Generally, twin disc clutches are smaller diameter. Most of the McLeod pieces I deal with are under 10" disc and pressure plate diameter. They may add a little weight, but it keeps it closer to the centerline of the crankshaft.
As for the cam, did your brother tell the builder that he was aiming for 700 hp and to put the peak hp up higher?
The 434 that I pictured peaked right at 7000 with 261/273 @ .050", but we ran a .904" lifter with a larger wheel diameter, which adds a couple degrees of duration. These heads flowed 380 on the intake side at .800". Generally speaking, the better the head flows, the less the duration needs to increase, as the head is more efficient. I had bought another camshaft to try on the dyno, 270/280 @ .050", but the engine made enough horsepower that we didn't try it. I have it on the shelf for when the engine comes back for a freshen-up. I expect that we would push over the 800 hp mark with it.
The out-of-the-box CHI 225cc head is probably 60 cfm lower than that from what I've seen on the flow bench. He would need a lot more camshaft than what I used to make up for the difference.
